1. Field of the Invention
The present invention relates to the field of manufacturing of integrated circuits.
2. Discussion of the Related Art
More specifically, in the field of integrated circuits, primary components have to be separated and more or less laterally isolated from one another. The most current technology to reach such results is the so-called LOCOS technology in which the various primary components are separated from one another by thick oxide layers formed by thermal growth. Another developing technique which tends is the so-called well isolation technology, called "BOX" technology. In BOX technology, the intervals between primary components are formed of trenches grooved by anisotropic etching into the upper surface of a single crystal silicon wafer and filled with an insulator, usually silicon oxide, the upper surface being planarized by several techniques, for example by chem-mech polishing (CMP) with a stop on a silicon nitride layer previously formed above the silicon area to be isolated.